'\" t
.TH "SD_BUS_SET_PROPERTY" "3" "" "systemd 256.7" "sd_bus_set_property"
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.SH "NAME"
sd_bus_set_property, sd_bus_set_propertyv, sd_bus_get_property, sd_bus_get_property_trivial, sd_bus_get_property_string, sd_bus_get_property_strv \- Set or query D\-Bus service properties
.SH "SYNOPSIS"
.sp
.ft B
.nf
#include <systemd/sd\-bus\&.h>
.fi
.ft
.HP \w'int\ sd_bus_set_property('u
.BI "int sd_bus_set_property(sd_bus\ *" "bus" ", const\ char\ *" "destination" ", const\ char\ *" "path" ", const\ char\ *" "interface" ", const\ char\ *" "member" ", sd_bus_error\ *" "ret_error" ", const\ char\ *" "type" ", \&.\&.\&.);"
.HP \w'int\ sd_bus_set_propertyv('u
.BI "int sd_bus_set_propertyv(sd_bus\ *" "bus" ", const\ char\ *" "destination" ", const\ char\ *" "path" ", const\ char\ *" "interface" ", const\ char\ *" "member" ", sd_bus_error\ *" "ret_error" ", const\ char\ *" "type" ", va_list\ " "ap" ");"
.HP \w'int\ sd_bus_get_property('u
.BI "int sd_bus_get_property(sd_bus\ *" "bus" ", const\ char\ *" "destination" ", const\ char\ *" "path" ", const\ char\ *" "interface" ", const\ char\ *" "member" ", sd_bus_error\ *" "ret_error" ", sd_bus_message\ **" "reply" ", const\ char\ *" "type" ");"
.HP \w'int\ sd_bus_get_property_trivial('u
.BI "int sd_bus_get_property_trivial(sd_bus\ *" "bus" ", const\ char\ *" "destination" ", const\ char\ *" "path" ", const\ char\ *" "interface" ", const\ char\ *" "member" ", sd_bus_error\ *" "ret_error" ", char\ " "type" ", void\ *" "ret_ptr" ");"
.HP \w'int\ sd_bus_get_property_string('u
.BI "int sd_bus_get_property_string(sd_bus\ *" "bus" ", const\ char\ *" "destination" ", const\ char\ *" "path" ", const\ char\ *" "interface" ", const\ char\ *" "member" ", sd_bus_error\ *" "ret_error" ", char\ **" "ret" ");"
.HP \w'int\ sd_bus_get_property_strv('u
.BI "int sd_bus_get_property_strv(sd_bus\ *" "bus" ", const\ char\ *" "destination" ", const\ char\ *" "path" ", const\ char\ *" "interface" ", const\ char\ *" "member" ", sd_bus_error\ *" "ret_error" ", char\ ***" "ret" ");"
.SH "DESCRIPTION"
.PP
These functions set or query D\-Bus properties\&. D\-Bus properties are service fields exposed via the
\fBorg\&.freedesktop\&.DBus\&.Properties\fR
interface\&. Under the hood, these functions call methods of the
\fBorg\&.freedesktop\&.DBus\&.Properties\fR
interface and as a result their semantics are similar to
\fBsd_bus_call_method\fR(3)\&.
.PP
\fBsd_bus_set_property()\fR
sets a D\-Bus property\&. If setting the property fails or an internal error occurs, an error is returned and an extended description of the error is optionally stored in
\fIret_error\fR
if it is not
\fBNULL\fR\&.
\fItype\fR
and the arguments that follow it describe the new value of the property and must follow the format described in
\fBsd_bus_message_append\fR(3)\&.
.PP
\fBsd_bus_set_propertyv()\fR
is equivalent to
\fBsd_bus_set_property()\fR, except that it is called with a
"va_list"
instead of a variable number of arguments\&.
.PP
\fBsd_bus_get_property()\fR
queries a D\-Bus property\&. If retrieving the property fails or an internal error occurs, an error is returned and an extended description of the error is optionally stored in
\fIret_error\fR
if it is not
\fBNULL\fR\&. On success, the property is stored in
\fIreply\fR\&.
\fItype\fR
describes the property type and must follow the format described in
\fBsd_bus_message_append\fR(3)\&.
.PP
\fBsd_bus_get_property_trivial()\fR,
\fBsd_bus_get_property_string()\fR
and
\fBsd_bus_get_property_strv()\fR
are shorthands for
\fBsd_bus_get_property()\fR
that are used to query basic, string and string vector properties respectively\&. The caller is responsible for freeing the string and string vector results stored in
\fIret\fR
by
\fBsd_bus_get_property_string()\fR
and
\fBsd_bus_get_property_strv()\fR\&.
.SH "RETURN VALUE"
.PP
On success, these functions return a non\-negative integer\&. On failure, they return a negative errno\-style error code\&.
.SS "Errors"
.PP
See the
\fBsd_bus_call_method\fR(3)
man page for a list of possible errors\&.
.SH "NOTES"
.PP
Functions described here are available as a shared library, which can be compiled against and linked to with the
\fBlibsystemd\fR\ \&\fBpkg-config\fR(1)
file\&.
.PP
The code described here uses
\fBgetenv\fR(3), which is declared to be not multi\-thread\-safe\&. This means that the code calling the functions described here must not call
\fBsetenv\fR(3)
from a parallel thread\&. It is recommended to only do calls to
\fBsetenv()\fR
from an early phase of the program when no other threads have been started\&.
.SH "HISTORY"
.PP
\fBsd_bus_set_property()\fR,
\fBsd_bus_set_propertyv()\fR,
\fBsd_bus_get_property()\fR,
\fBsd_bus_get_property_trivial()\fR,
\fBsd_bus_get_property_string()\fR, and
\fBsd_bus_get_property_strv()\fR
were added in version 246\&.
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1), \fBsd-bus\fR(3), \fBsd_bus_call_method\fR(3)
